1. Field of the Invention
The present invention relates to a plasma albumin medicine. More particularly, it relates to a process for separating a substantially pure plasma albumin from blood plasma.
2. Description of the Prior Arts
Recently, blood has been used for not only the blood transfusion for the emergency life saving but also the blood storage and the preparation of blood medicines. Because of such technical development, only the important blood component is separated and transfused whereby it is possible to administrate at a desired dose and to prevent side-effects caused by needless components and to effectively utilize human blood which is the important minor source.
It has been well-known that blood can be separated into erythrocyte, leukocyte, blood platelets, and liquid blood plasma. The blood plasma contains various proteins which have different functions. It is desirable that the proteins of blood plasma are separated and purified and only desired component fraction is used depending upon the purpose. Among the proteins of blood plasma, plasma albumin has function for maintaining osmotic pressure of blood, and transferring biologically indispensable materials such as nutrition to various organs.
The medical applications of plasma albumin include therapy for hypoalbuminemia and edema caused by hypoalbuminemia; emergency therapy for hemorrhagic shock or burns and removement of plasma bilirubin in exchange transfusion of new born, etc. Excellent results have been attained in these applications.
As processes for separating plasma albumin from blood plasma, it has been known to utilize difference of solubilities of molecules difference of charges and sizes of molecules as follows:
(1) a fractional precipitation by addition of a neutral salt such as ammonium sulfate; or an organic solvent such as cold ethanol or a water soluble macromolecule such as polyethyleneglycol;
(2) a chromatography using an ion exchanger or an adsorbent or a molecular seive etc.;
(3) an electrophoretic process based on difference of charges;
(4) an immunoadsorption.
The above-mentioned process or combination thereof has been employed. These processes have disadvantages to cause damage of structure of the plasma protein molecule by the operation at room temperature; to form aggregate; to require a long time for separation or a precise operation.